Fuse for automatic destruction of shells



G. HQNGER Filed May 27, 1941 7 III.

Aug. 13, 1946.

FUSE FOR AUTOMATIC DESTRUCTION 0F SHELLS lllllllllll lllllll Patented Aug. 13, 1946 FUSE FOR AUTOMATIC DESTRUCTION OF SHELLS Guido Hiinger, Geneva, Switzerland Application May 2'1, 1941, Serial No. 395,466 In Switzerland July 9, 1940 2 Claims.

Various designs of fuses for projectiles have been evolved in recent years in connection with antiaircraft defense, in which a mechanism is released when the angular velocity of the projectile falls below a critical and assigned value, thus allowing the striker to set off the detonator and produce automatic destruction of the shell.

The known fuses have the serious defect that; the critical angular velocity being but little inferior to the initial velocity it is quite possible that this critical value may never be reached, for instance in case of slightly defective propelling charges. The result is a premature explosion of the shell at the instant the linear acceleration vanishes, that is a foot or so from the gun.

The present invention has for its object to overcome this inconvenience. A premature explosion which might otherwise result from an insufficient propellent loading is prevented by a special mechanism. The transport safety device can free the other mechanism when and only when the velocity of rotation of the projectile exceeds the just described critical velocity by a definite amount which may be chosen at will. This invention does not impair the desirable qualities of the shells known up to date such as safety in transport, high sensitivity of percussion, ease of manufacture of large quantities, as well as low cost.

The figure illustrates an application of the invention to such a fuse. During transport the striker if] is secured. in the known manner by centrifugal weights I I, kept in place by the light pressure of a leaf spring l2; under the pressure of a coil spring [4, a tube l3 locks the centrifugal weights ll; two cylindrical weights l5 with rounded nose are free to move in appropriate radial holes bored in a head l3a of the tube l3. At the instant propulsion takes place, owing to inertia, the pressure of the lower end l3b of the tube l3 on the centrifugal weights H is increased so that in spite of the centrifugal forces developed the safeties remain unaltered.

Not until the linear acceleration nearly stops can the centrifugal weights 1 5 begin to act. They press against the slanting surfaces I6 of a sleeve lBa forming a guide for the tube parts I3, l3a and gradually pull the tube I3 forward compressing the coil spring 14, thereby releasing the centrifugal weight I l which move radially owing to the rotation of the projectile and free the striker It. The shell is then armed and it will explode the instant it hits any part of the aircraft.

Should the projectile not encounter any obstacle, it would follow its course undisturbed and after a certain time explode automatically as will be shown.

The angular velocity gradually decreasing while the projectile follows its trajectory, the centrifugal forces acting upon the weights [5 are no longer sufficient to balance the spring Hi; the tube I3 gradually glides backward, the nose of the weights l5 reaches the end ll of the slanted surfaces I6, the coil spring l4 acts unhampered on the tube [3 which throws the striker l0 against the detonator it! thus producing the automatic destruction of the shell.

On the contrary, if during propulsion the critical value of the angular velocity is not reached, owing to a faulty loading of propellant for instance, the centrifugal forces exerted by the weights I 5 will not suffice to pull the tube 13 forward. The centrifugal weights ll remain locked thereby keeping the striker l0 locked as well. Under these conditions the shell may hit an obstacle, the ground in particular, without exploding.

I claim:

1. A sensitive percussion fuse for projectiles comprising a fuse body, a detonator therein, a striker having percussion means associated therewith, a tubular member coaxial with and surrounding the striker said member being axially slidable in the fuse body, an internal shoulder on said tubular member, a spring within said tubular member and abutting between said shoulder and the fuse body, centrifugally operated transport safety means normally held by the inner end of said tubular member in position separating said striker from said detonator, means on said tubular member for driving the striker towards said detonator under the action of said spring and having a one-way connection with the striker enabling the striker to move towards the detonator without restraint from said tubular member, a head on said tubular member, centrifugal weights of cylindrical form having rounded ends slidable radially in said head, and an internal conical ramp on the fuse body cooperating with the rounded ends of said weights to produce axial movement of said tubular member, the centrifugal action of said weights being predetermined to overcome said spring only above a critical angular velocity of the fuse.

2. A sensitive percussion fuse for projectiles comprising a fuse body having a cylindrical axial bore therein of uniform diameter, a detonator in said body, a guide sleeve lodged in said bore and having an internal ramp at its outer end, a member with a head having radial cavities therein and a tubular stem both said head and ing a one-way connection with the striker enenabling the striker to move towards the detonator without restraint from said tubular member, centrifugal weights of cylindrical form having rounded ends slidable in said radial cavities with the rounded ends engaging said internal ramp to produce axial movement of said member, the centrifugal action of said weights being predetermined to overcome said spring only above a 10 critical angular velocity of the fuse.

GUIDO HNGER. 

